Bio-inspired nanostructured surfaces are covered with nanometer scale features which, depending on their size and spacing, can produce valuable properties [1]. Nanofeatures found on the surface of moth eyes create an anti-reflective (AR) property which can serve as a defense mechanism for this nocturnal insect by blending the index of refraction from the air to the eye surface [2, 3]. Similar tapered features can be placed on a surface creating a gradual change in index of refraction from the air to the surface preventing a sharp change in index of refraction at the air-surface interface reducing Fresnel reflection [4-7]. For nanofeatures to produce the AR property the period of the features must be less than the wavelength in the visible spectrum (380-750 nm) [8, 9]. These types of surfaces can be useful in photovoltaic applications because of their ability to perform over multiple wavelengths of light and large viewing angles [10-14]. Structures found on the surface of the lotus leaf produce a superhydrophobic effect where water droplets sit on the surface with a very high contact angle (>150°) [15, 16]. Water droplets roll off the leaf surface easily due to this high contact angle and pick up debris along the way to clean the surface. This property would also be attractive for photovoltaic cell coatings where build-up from operating in an outdoor environment is inevitable. While both properties are desirable, the main focus of this research has been on generating AR (optical) nanofeatures.
The use of nanostructured surfaces like the ones found on moth eyes has become increasingly popular in consumer and commercial applications. The advantages of structured surfaces have been recognized and the demand for inexpensive coatings is high. The limitation of these nanostructured surfaces is the length of time required to produce a usable quantity. Current techniques for generating nanostructured surfaces have been successful but are not feasible because of long manufacturing times. Lithography methods are popular and can produce a limited area of high quality features, but suffer from a large number of manufacturing steps (spin coating, baking, etching, . . . ) as well as long duration (the baking can take 10 h) [17, 18].
Accordingly, there exists a need for methods and systems for fast imprinting of nanometer scale features in a workpiece.